Consider challenging them to an intellectual battle instead. Remember that you are strong and capable.
Guard your face, as your head is the most sensitive part of you. Bend your arms and hold them in front of your face. Keep your hands clenched into fists so that you can be ready to punch if necessary.
You can certainly use objects as a shield, such as holding up a book to block blows. However, you will lose the respect of your peers if you use such objects against your opponent and the odds become uneven and unfair.
Remember that it takes strength and bravery to try to avoid a fight altogether.
